China Nonferrous Metallurgy

Aiming at the poor separation effect of metal from slag because of TiC in slag in the process of titanomagnetite smelting in electric furnace, a new method of carbothermal pre-reduction-silicothermal reduction melting separation is proposed in this paper. That is in the later stage of the reduction process, silicon was used instead of carbon for reduction reaction to avoid the formation of TiC, and the condition test and product and slag detection analysis were carried out.The condition tests of carbon thermal pre-reduction show that low carbon (-C-=012%~022%) products can be obtained at 1200℃ by controlling reaction time and carbon content (16~19 times of theoretical carbon ratio). The condition tests of siliconthermal reduction smelting show that the yield of V increases with the increase of Si ratio, and the yield of Fe increases with the increase of Si ratio. Under the same Si ratio, the lower the C ratio in the pre-reduction stage, the lower the Fe yield and the higher the V yield. When the Si ratio is increased to 18 Si, the V yield is 7771%~8162% and the Fe yield is 9723%~9989% under different carbon ratios, and the separation effect of metal from slag is good. Slag X-ray diffraction spectrum shows that the main phases in the slag are magnesium aluminum titanate (Mg₄Al₂Ti₉O₂₅) and magnesium aluminum spinel (MgAl₂O₄), without TiC. According to the spectrum and energy spectrum, it is calculated that with the increase of Si ratio, the content of TiO₂ in slag increases, which can be controlled at 2728%~3486% when the ratio of Si is 18. This method uses Si instead of C for deep reduction, which significantly improves the yield of V. The recovered vanadium can make up for the cost caused by silicon consumption, and the potential economic benefits are significant.